The prime objective of this program is to use advanced integrated circuit technology directly to help solve the problems of medical research and practice. The essence of the program is the use of custom integrated circuits and transducer arrays, designed and fabricated for use in a particular medical instrument. The program is divided into four projects: large scale integration, integrated circuit transducers, telemetry systems and advanced technology. Effort in the advanced technology has been aimed largely at support of the large scale integration project. Effort under the integrated circuit transducers project has been largely in support of the telemetry systems project. The principal problem pursued in the large scale integration project is the development of a unique ultrasonic imaging system, dubbed ULISYS. Although commercial ultrasonic diagnostic equipment is used in medicine, it suffers from the limitation of a single element transducer. Thus, the amount of information presented to a user is less than in our ultrasonic imaging system. It will use several thousand transducer elements in a monolithic array and provide images of planes both perpendicular and parallel to the direction of sound travel and in real time. The principal telemetry systems problem is to develop a family of chronically implantable blood flowmeters, which had not been developed before. These are needed in a wide variety of research investigations using animals. Another project has produced a new intraoperative blood flowmeter which has been used during cardiac surgery on a number of patients. Progress has been made to develop a transcutaneous blood flowmeter to analyze the behavior of the vascular system.